The present invention relates to a device for filtering impure liquids. More particularly, it pertains to a faucet-attachment water filter assembly together with a replaceable filter housing for filtering water flow. The internally by-passable purifier apparatus permits the selective distribution from a common source of either purified or non-purified water.
Various impurities, such as minerals, chlorine, and particulates, often enter domestic tap water to affect the taste, odor, appearance and healthfulness of the water. A significant percentage of water obtained from individual taps in the home and the like contains these chemical constituents in amounts that exceed limits set forth in standards issued by public health services. In some cases, such samples evidence a potential danger. Various studies have identified a need for improved systems to control at least aesthetically undesired concentrations of various minerals and other constituents as well as color, taste and odor. The problem is one of both preventing the transmission of disease or the like as well as overcoming effects that may be adverse to the sensibilities of the user.
In order to remove these impurities, point-of-use filtration devices have become increasingly popular in the home. These have included in-line filters, under-the-sink filters, free-standing drink-size separate filter units, and filter devices that attach to the conventional sink faucet or to the typical aerator secured thereto.
However, the addition of a water purifying apparatus has frequently meant the undesired occupation of counterspace, under-sink space or interference to convenient utilization because of the need for flexible hoses. In fact, to achieve comparatively low cost in such apparatus, manufacturers have been led to the production of units which attain that objective only at the expense of interference with space utilization or aesthetic unattractiveness.
Faucet-attachment types of water filters have become a viable commercial product, possibly by reason of the fact that they do not require changes in plumbing to allow their use in the home or similar environment. See, for example, U.S. Pat. No. 3,853,761 to McClory, U.S. Pat. No. 4,172,796 to Corder, U.S. Pat. No. 4,359,384 to Brane, U.S. Pat. No. 4,504,389 to Rundzaitis, and U.S. Pat. No. 4,686,037 to Lang. Typically, they attach to the outlet of a faucet in the kitchen sink and include valving to permit flow of either tap or filtered water, the water to be filtered flowing through a replaceable cartridge mounted upon one portion of the appliance. The usual cartridge includes activated charcoal granules, impregnated carbon paper, or impregnated carbon cotton effective in removing tastes and odors from the water.
However, this type of prior art device has had the disadvantages that the operation of the valve unit is not always reliable and tap water leaks from the valve unit while purified water is being obtained, and that the valve unit becomes unserviceable in a relatively short period of time due to wear of the valve element disposed therein. In addition, the valve unit has been complicated in construction and hence difficult to manufacture, and the mounting of the valve unit on the faucet has also been difficult.
Equally important, many of the devices in the prior art have cartridge filters that do not filter the water adequately and, moreover, require the entire water filter apparatus to be disconnected from the water faucet in order to replace the cartridge filter in the apparatus. Furthermore, the upward extension of the filter cartridge in a vertical plane above the faucet is considered, by many consumers, to be aesthetically unattractive.
In summary, prior art apparatus and filter mechanisms have not been as efficient as they might be, and they also have not led to efficiencies in manufacture. Furthermore, they have sometimes been aesthetically unattractive for household use.